Fixes <https://bugs.gnu.org/39727>. Reported by Paul Garlick <pgarlick@tourbillion-technology.com>. * nix/libstore/gc.cc (LocalStore::removeUnusedLinks) [HAVE_STATX]: Add 'statx_flags' static variables. Clear 'AT_STATX_DONT_SYNC' flag from 'statx_flags' when 'statx' returns EINVAL.